This document discusses different types of chromosomal mutations including changes in structure (chromosomal aberrations) and number (genomic mutations). It describes several chromosomal aberrations like deletions, duplications, inversions, translocations and how they can affect the chromosome structure. It also discusses genomic mutations involving gains or losses of whole chromosomes called aneuploidy, and cases of polyploidy involving multiple chromosome sets. Specific examples of sex chromosome aneuploidy like Klinefelter syndrome and Turner syndrome are provided.

1. CHROMOSOMES
MUTAIONS

2. PLAN OF LECTURE
1. MUTATION AND ITS TYPES.
2. CHROMOSOMAL ABERRATIONS:
1)DELETION; 2) DUPLICATION; 3) INVERSION;
4) TRANSLOCATION.
3. GENOMIC MUTATION (CHROMOSOME MUTATION):
1) POLYPLOIDY; 2) ANEUPLOIDY.
4. AUTOSOMAL MUTATIONS.
5. SEX-CHROMOSOMES MUTATIONS.

3. You should prepare for the practical class
using the existing textbook and lecture
Applicable literature materials:
Medical biology / K. L. Lasarev – Simferopol: IAD
CSMU, 2002 p.181 - 188.
Key words and phrases:
mutation, genomic mutation, polyploidy,
aneuploidy, chromosomal aberrations, deletion,
duplication, inversion, translocation, oncogene,
aneuploidy (heteroploidy), euploidy (polyploidy),
monosomy, trisomy, autosomal trisomic, sex-
chromosome polysomy, monosomy X.

4. HEREDITARY
INFORMATION LIES
IN CHROMOSOMES.
THE EUKARYOTIC
CHROMOSOMES
ARE LOCATED WITHIN
THE NUCLEUS OF THE
CELL.

5. MUTATION VARIABILITY
• MUTATION - A PERMANENT TRANSMISSIBLE
CHANGE IN THE GENETIC MATERIAL,
MODIFICATION IN CHROMOSOMES AND GENES.
• CHROMOSOMAL MUTATIONS MAY BE THE
RESULT OF CHANGES IN THE STRUCTURE OR
NUMBER OF CHROMOSOMES.
• THERE ARE 2 MAIN TYPES OF CHROMOSOMES
MUTATIONS:

6. 1.CHROMOSOMAL ABERRATIONS - CHANGES
IN STRUCTURE OF CHROMOSOMES.
2.GENOMIC MUTATION - CHANGES IN
NUMBER OF CHROMOSOMES.
CERTAIN FORMS OF CHROMOSOMAL
MUTATION MAY AFFECT SEVERAL GENES AND
HAVE A MORE PROFOUND EFFECT ON THE
PHENOTYPE THAN GENE MUTATIONS.

7. CHROMOSOMAL ABERRATIONS - CHANGES IN
STRUCTURE OF CHROMOSOMES

8. CHROMOSOMAL MUTATIONS
OR ABERRATIONS

9. INVERSION
A SEGMENT OF A CHROMOSOME SEPARATES
AND REJOINS IT IN AN INVERTED POSITION.
INVERSION CHANGES THE SEQUENCE OF
NITROGENOUS BASES IN THE CHROMOSOMES.
INVERSION OCCURS WHEN A REGION OF A
CHROMOSOME BREAKS OFF AND ROTATES
THROUGH 180° BEFORE REJOINING THE
CHROMOSOME.

10. INVERSION
NO CHANGE IN GENOTYPE OCCURS AS A
RESULT OF INVERSION BUT PHENOTYPIC
CHANGES MAY BE SEEN.
THIS SUGGESTS THAT THE ORDER OF GENE
LOCI ON THE CHROMOSOME IS IMPORTANT, A
PHENOMENON KNOWN AS THE
POSITION EFFECT.

11. TRANSLOCATION
A SEGMENT OF CHROMOSOME BREAKS
OFF AND JOINS A NONHOMOLOGOUS
CHROMOSOME.
BOTH THE AFFECTED CHROMOSOMES
GET MODIFIED. THE DONOR SUFFERS
DELETION AND BECOMES SHORTER
THAN NORMAL. THE RECIPIENT HAS AN
EXTRA SET OF GENES AND BECOMES
LONGER THAN NORMAL.

14. RECIPROCAL TRANSLOCATION
RECIPROCAL TRANSLOCATION BETWEEN
NONHOMOLOGOUS CHROMOSOMES CAN
PRODUCE TWO NEW HOMOLOGOUS PAIRS
OF CHROMOSOMES.

16. ROBERTSONIAN TRANSLOCATION
ROBERTSONIAN TRANSLOCATION –
SPECIAL SORT WHERE THERE IS
NONRECIPROCAL EXCHANGES OF DNA,
FUSION OF TWO ACROCENTRICS TO GIVE
A METACENTRIC, CENTROMERIC FUSION.

18. ROBERTSONIAN TRANSLOCATION

19. IN SOME CASES OF DOWN'S SYNDROME, WHERE THE DIPLOID
NUMBER IS NORMAL, THE EFFECTS ARE PRODUCED BY THE
TRANSLOCATION OF AN EXTRA 21 CHROMOSOME ONTO A
LARGER CHROMOSOME, USUALLY 13,14,15.

20. DELETION
A SEGMENT OF A CHROMOSOME
SEPARATES AND IS LOST.
THE AFFECTED CHROMOSOME LOSES
CERTAIN GENES, AND BECOMES SHORTER
THAN NORMAL.
IF DELETION AFFECTS THE SAME GENE LOCI
ON BOTH HOMOLOGOUS CHROMOSOMES THE
EFFECT IS USUALLY LETHAL.

22. DUPLICATION
A FRAGMENT OF A CHROMOSOME
JOINS A HOMOLOGOUS CHROMOSOME.
THE ADDITIONAL REGION OF GENES
MAY BE INCORPORATED WITHIN THE
CHROMOSOME OR AT ONE END OF THE
CHROMOSOME, OR BECOME ATTACHED TO
ANOTHER CHROMOSOME.
THESE CHANGES, IF NOT LETHAL, MAY
CAUSE PROFOUND CHANGES IN THE
PHENOTYPE.

24. CHROMOSOME ABNORMALITIES AND CANCER
TRANSLOCATIONS AND INVERSIONS CREATE
NEW ARRANGEMENTS OF GENES, SOME
GENES ARE MORE HIGHLY EXPRESSED OR
ARE MUCH LESS EXPRESSED, THERE ARE
"POSITION EFFECTS" ON GENE EXPRESSION,
SOME OF THESE CHANGES LEAD TO
CANCER, OVEREXPRESSION OF AN
ONCOGENE OR UNDEREXPRESSION OF A
TUMOR SUPPRESSOR GENE CAN LEAD TO
CANCER.

25. CHROMOSOME ABNORMALITIES AND CANCER

26. GENOMIC MUTATION
CHANGES IN THE NUMBER OF
CHROMOSOMES ARE USUALLY THE
RESULT OF ERRORS OCCURRING
DURING MEIOSIS BUT THEY CAN ALSO
OCCUR DURING MITOSIS. THESE
CHANGES MAY INVOLVE THE LOSS OR
GAIN OF SINGLE CHROMOSOMES, A
CONDITION CALLED ANEUPLOIDY OR
HETEROPLOIDY.

27. ANEUPLOIDY - HETEROPLOIDY
MONOSOMY – LOSS OF A CHROMOSOME,
SO A "DIPLOID -1" , HAS ONLY ONE COPY
OF A PARTICULAR CHROMOSOME RATHER
THEN TWO.
EXAMPLE: MONOSOMIC (2N-1), 45(X0)
TRISOMY – GAIN OF A CHROMOSOME SO
THERE ARE THREE OF ONE SORT/
EXAMPLE: TRISOMIC (2N+1), 47 (XXX)

28. SEX-CHROMOSOMES MUTATIONS
ANEUPLOIDY IS THE LOSS OR GAIN OF
SINGLE CHROMOSOMES, NUMERAL
CHANGES (ANEUPLOIDY) IN SEX
CHROMOSOMES.
SEX-CHROMOSOME POLYSOMY
A. TRIPLE X: (47, XXX); TRISOMY X;
FEMALE.
B. DOUBLE Y: (47,XYY); TRISOMY; DISOMY
Y; MALE.

29. C. KLINEFELTER SYNDROME; (47, XXY);
TRISOMY; MALE.
THESE INDIVIDUALS TEND TO BE TALL,
STERILE, WITH MILD MENTAL RETARDATION
D. TURNER SYNDROME; (45, XO);
MONOSOMY X; FEMALE.
THESE INDIVIDUALS TEND TO BE SHORT,
STERILE, WITH NORMAL MENTAL
DEVELOPMENT

30. Sex-chromosome polysomy
a. triple X: (47, XXX); trisomy X;

31. POLYPLOIDY
THE INCREASE IN ENTIRE HAPLOID
SETS OF CHROMOSOMES, A
CONDITION CALLED POLYPLOIDY.
MONOPLOID CHROMOSOME SET
1N – THE BASIC CHROMOSOME SET
OF A SPECIES.

32. POLYPLOIDY, HAVING A PERFECT,
BALANCED CHROMOSOME
COMPLEMENT.
HUMAN TRIPLOIDS 3N=69 AND
TETRAPLOIDS 4N=92 ARE NOT
VIABLE. POLYPLOID HUMAN
EMBRION DIE. BUT TETRAPLOID
CELLS IN NORMAL MAY BE IN HUMAN
LIVER.

33. AUTOPOLYPLOIDY

34. MOSAICISM

36. TWO TYPES OF MOSAICISM

39. MOSAICISM

40. MOSAICISM

41. DO YOU HAVE
A QUESTIONES?
THE END